1385643 - Intl.DateTimeFormat().format returns wrong month names for some historical dates

Status: RESOLVED DUPLICATE of bug 1346211

(Core :: JavaScript: Standard Library, defect, P5)

Description

[Wojciech Maj]

Attachment: Check month names validity 1900-2100.txt

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36 Edge/16.16251

Steps to reproduce:

1. Set your timezone to Warsaw time (UTC +2:00)
2. Run the code from the attached file in browser console
3. Observe results



Actual results:

In years 1900-1915:
Months April-October are shifted by -1 (April becomes March, May becomes April etc.)

In year 1916:
April is shifted by -1

In year 1917:
April is shifted by -1
October is shifted by -1

and so on, and so on.



Expected results:

All month names shall be correct for all dates.

Comment 1

[j.j.]

Attachment: test with HTML output

Google Chrome has the same output, no?

Comment 2

[André Bargull [:anba]]

Providing the time in milliseconds since the start of the Unix epoch, i.e. |new Date(-1885683600000 - 24*60*1000).toLocaleString(undefined, {timeZone:"Europe/Warsaw"})|, returns the correct date, which indicates that this is an issue converting the local time to a UTC offset -> bug 1346211.

Comment 3

[André Bargull [:anba]]

Dup'ing forward to bug 1346211 which should have fixed this problem. Please reopen if the issue is still present. Thanks!